WO2009145150A1

WO2009145150A1 - Adhesive polarization plate, image display device and methods for manufacturing adhesive polarization plate and image display device

Info

Publication number: WO2009145150A1
Application number: PCT/JP2009/059540
Authority: WO
Inventors: 暢鈴木; 山本　昌司; 武田　健太郎; 恒三中村; 悠杉本
Original assignee: 日東電工株式会社
Priority date: 2008-05-27
Filing date: 2009-05-25
Publication date: 2009-12-03
Also published as: EP2290413A1; US20130098524A1; KR20110014555A; JP5324316B2; PL2290413T3; US20130126085A1; CN101978295A; EP2290413A4; EP2290413B1; JP2010009027A; EP2535748A1; TW201007229A; TWI467250B; US20110043733A1; KR101673037B1

Abstract

Provided is an adhesive polarization plate wherein a transparent protection film (E) is arranged only on one surface of a polarizer (P) with an adhesive layer (G) therebetween, and on the other surface of the polarizer (P), an adhesive layer (B) is arranged with a protection layer (H) having an elongation modulus of 100 MPa or more therebetween. The adhesive polarization plate satisfies durability even under severe environments at a low temperature and a high temperature.

Description

Adhesive polarizing plate, image display device, and manufacturing method thereof

The present invention relates to an adhesive polarizing plate in which a transparent protective film is provided only on one side of a polarizer and an adhesive layer is laminated on the other side, and a method for producing the same. Furthermore, the present invention relates to an image display device using the adhesive polarizing plate. Furthermore, the present invention relates to a method for manufacturing the image display device.

In a liquid crystal display device, it is indispensable to dispose polarizing plates on both sides of a glass substrate that forms the surface of the liquid crystal panel because of its image forming method. In general, a polarizing plate is made of a polyvinyl alcohol-based film and a transparent protective film for a polarizer using triacetyl cellulose or the like on one or both sides of a polarizer made of a dichroic material such as iodine. What was bonded together by the agent (patent document 1, patent document 2) is used. In addition, the durability performance required for polarizing plates has become strict, and durability under harsh environments at low and high temperatures is required.

When adhering the polarizing plate to a liquid crystal cell or the like, an adhesive is usually used. In addition, the adhesive is provided as an adhesive layer in advance on one side of the polarizing plate because it has the merits of being able to fix the polarizing plate instantly and not requiring a drying step to fix the polarizing plate. . That is, an adhesive polarizing plate is generally used for attaching the polarizing plate.

JP 2006-220732 A JP 2001-296427 A

The pressure-sensitive adhesive layer is usually applied to a polarizing plate provided with a transparent protective film on both sides of a polarizer, and the pressure-sensitive adhesive layer is laminated on the transparent protective film in the polarizing plate. On the other hand, from the viewpoint of thinning, a polarizing plate provided with a transparent protective film only on one side of the polarizer is used. In the polarizing plate, an adhesive layer is provided on the other side of the polarizer. However, a thin adhesive polarizing plate provided with a transparent protective film only on one side of the polarizer has poor durability, and cracks tend to occur in the stretching direction (MD direction) of the polarizer when placed in the harsh environment. There's a problem. In particular, the occurrence of the crack is likely to occur when the size of the polarizing plate is increased.

Also, a polarizing plate in which a protective film is formed on at least one side of a polarizer has been proposed (Patent No. 4131104) for the problem of thinning. However, the polarizing plate is a thin adhesive type in which a protective film is formed directly on a polarizer instead of a transparent protective film, and a transparent protective film is provided only on one side of the polarizer for the problem of thinning. No mention is made of the occurrence of cracks in the polarizer that occurs in the polarizing plate, and the problem is not recalled.

The present invention is a pressure-sensitive adhesive polarizing plate having a transparent protective film only on one side of a polarizer and having an adhesive layer on the other side, and placed in a harsh environment at low and high temperatures. Another object of the present invention is to provide an adhesive polarizing plate capable of satisfying durability.

Another object of the present invention is to provide an image display device having the above-mentioned adhesive polarizing plate and a method for producing the same.

As a result of intensive studies, the inventors of the present application have found that the above-described problems can be solved by the following adhesive polarizing plate, and have reached the present invention.

That is, in the present invention, the transparent protective film (E) is provided only on one side of the polarizer (P) via the adhesive layer (G), and the other side of the polarizer (P) has tensile elasticity. The present invention relates to a pressure-sensitive adhesive polarizing plate characterized in that a pressure-sensitive adhesive layer (B) is provided through a protective layer (H) having a rate of 100 MPa or more.

In the adhesive polarizing plate, the protective layer forming agent (H ′) for forming the protective layer (H) is a cyanoacrylate-based forming agent, an epoxy-based forming agent, an isocyanate-based forming agent, or an acrylic-based forming agent. Is preferred.

In the pressure-sensitive adhesive polarizing plate, the protective layer forming agent (H ′) for forming the protective layer (H) is preferably an active energy ray curable forming agent containing a curable component.

In the pressure-sensitive adhesive polarizing plate, the protective layer (H) preferably satisfies a photoelastic coefficient (m ² / N) × thickness (m) ≦ 1 × 10 ⁻¹⁴ (m ² / N).

In the present invention, the transparent protective film (E) is provided only on one side of the polarizer (P) via the adhesive layer (G), and the other side of the polarizer (P) has a protective layer. (H) is a method for producing a pressure-sensitive adhesive polarizing plate provided with a pressure-sensitive adhesive layer (B),
The protective layer (H) has a tensile modulus of 100 MPa or more,
In the lamination of the polarizer (P) and the pressure-sensitive adhesive layer (B), a protective layer (H) is formed on one surface of the polarizer (P), and then the pressure-sensitive adhesive layer (B) is formed on the protective layer (H). It is related with the manufacturing method of the adhesion type polarizing plate characterized by performing by laminating | stacking.

In the method for producing an adhesive polarizing plate, the protective layer forming agent (H ′) for forming the protective layer (H) is a cyanoacrylate-based forming agent, an epoxy-based forming agent, an isocyanate-based forming agent, or an acrylic-based forming agent. It is preferable that

In the method for producing an adhesive polarizing plate, the protective layer forming agent (H ′) for forming the protective layer (H) is preferably an active energy ray curable forming agent containing a curable component.

In the method for producing an adhesive polarizing plate, the protective layer (H) preferably satisfies a photoelastic coefficient (m ² / N) × thickness (m) ≦ 1 × 10 ⁻¹⁴ (m ² / N). .

The present invention also relates to an image display device having the pressure-sensitive adhesive polarizing plate.

Further, the present invention is a method for manufacturing the image display device, a roll raw fabric preparation step of preparing a long sheet of the pressure-sensitive adhesive polarizing plate as a roll raw fabric, a sheet product is fed out from the roll raw fabric, and cut A cutting step of cutting the pressure-sensitive adhesive polarizing plate into a predetermined size using means, and a bonding step of bonding to the optical display unit via the pressure-sensitive adhesive layer (B) of the pressure-sensitive adhesive polarizing plate after the cutting step; The present invention relates to a method for manufacturing an image display apparatus having

The mechanism of crack generation in the polarizer is assumed as follows. That is, the polarizer is usually produced by dyeing and stretching a polyvinyl alcohol film, but is highly stretched in order to exhibit its high polarization characteristics. Therefore, since the polyvinyl alcohol-based molecule exhibits high orientation, it has a very high strength in the stretching direction (MD direction), but has a mechanical property that the TD direction perpendicular thereto is very brittle. Therefore, when an external stress is applied to the polarizer, cracks are easily generated in the MD direction. This crack causes a serious problem with respect to the display characteristics of the image display device. Examples of the external stress include humidification / drying, heating / cooling, mechanical tension, compression, bending, and the like. In particular, as for humidification / drying, since the polarizer material uses hydrophilic polyvinyl alcohol or the like as a raw material, moisture is adsorbed / released by the external environment, thereby causing expansion and contraction of the polarizer. In particular, the moisture absorption of the polarizer ranges from about 5% to 30% by weight and exhibits volume shrinkage / expansion therebetween. In order to prevent scratches on the surface of the polarizer, to prevent such sudden entry and exit of moisture, and to prevent changes that occur in the polarizer, and to mechanically hold the polarizer, A protective film is used on both sides of the child. The same applies to heating / cooling, and the transparent protective film functions to suppress expansion and contraction associated with thermal expansion of the polarizer. The transparent protective film supports the stress applied to the polarizer against external forces such as mechanical tension and compression, thereby suppressing the occurrence of polarizer cracks and the like. On the other hand, in the case where the transparent protective film is a polarizing plate that is only on one side of the polarizer, the polarizing plate has an asymmetric configuration and the one side of the polarizer is in a free state. Occurrence could not be suppressed. The pressure-sensitive adhesive layer may have a low density, and its deterrence ability is small with respect to the ingress of moisture, and the elastic modulus is very small, so the mechanical holding ability of the polarizer is very small and it can be said that it is free. It is.

The adhesive polarizing plate of the present invention has a transparent protective film (E) only on one side of the polarizer (P), and a thin type having an adhesive layer (B) on the other side of the polarizer (P). Although it is an adhesive-type polarizing plate, a protective layer (H) having a tensile elastic modulus of 100 MPa or more is provided between the adhesive layer (B) and the polarizer (P), and the protective layer (H) Even in a harsh environment, cracks in the MD direction of the polarizer can be suppressed, and durability can be satisfied.

In addition, the pressure-sensitive adhesive polarizing plate of the present invention is thin, but has good durability even in a harsh environment. Therefore, when manufacturing an image display device using the pressure-sensitive adhesive polarizing plate, Work efficiency is good. In particular, it is suitable in the manufacturing method of the image display apparatus which performs from the roll original fabric preparation process of an adhesion type polarizing plate to a cutting process and the bonding process bonded together to an optical display unit as a series of processes.

It is a schematic sectional drawing of the adhesion type polarizing plate by preferable embodiment of this invention. It is a flowchart which shows an example of the manufacturing method of the conventional optical display unit.

Hereinafter, the adhesive polarizing plate of the present invention will be described with reference to FIG. In the pressure-sensitive adhesive polarizing plate of the present invention, for example, as shown in FIG. 1, a transparent protective film (E) is provided only on one side of a polarizer (P) via an adhesive layer (G). On the other side of the child (P), an adhesive layer (B) is provided via a protective layer (H). Although not shown, the pressure-sensitive adhesive polarizing plate of the present invention is provided with an easy-adhesion layer or an activation treatment on the transparent protective film (E) so that the easy-adhesion layer and the adhesive layer (G ) Can be pasted together. Although not shown, a release sheet can be provided on the pressure-sensitive adhesive layer (B).

The size of the pressure-sensitive adhesive polarizing plate of the present invention is not particularly limited, but the diagonal value is preferably in the range of 14 inches to 120 inches. This is because as the size increases, cracks are more likely to occur in a harsh environment in a thin adhesive polarizing plate having a transparent protective film only on one side. The size may of course be smaller than 14 inches. Usually, the size is 82 inches or less.

[Polarizer]
A polarizer refers to a film that can be converted from natural light or polarized light into arbitrary polarized light. Any appropriate polarizer may be adopted as the polarizer used in the present invention, but a polarizer that converts natural light or polarized light into linearly polarized light is preferably used.

In the polarizing plate of the present invention, any appropriate polarizer (P) can be adopted depending on the purpose. For example, dichroic substances such as iodine and dichroic dyes are adsorbed on hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene / vinyl acetate copolymer partially saponified films. And a polyene-based oriented film such as a uniaxially stretched product, a polyvinyl alcohol dehydrated product or a polyvinyl chloride dehydrochlorinated product. Further, a guest / host type O-type polarizer in which a liquid crystalline composition containing a dichroic substance and a liquid crystalline compound disclosed in US Pat. No. 5,523,863 is aligned in a certain direction, US Pat. An E-type polarizer or the like in which lyotropic liquid crystals disclosed in US Pat. No. 6,049,428 are aligned in a certain direction can also be used.

Among such polarizers, from the viewpoint of having a high degree of polarization, a polarizer made of a polyvinyl alcohol film containing iodine is preferably used. Polyvinyl alcohol or a derivative thereof is used as a material for the polyvinyl alcohol film applied to the polarizer. Derivatives of polyvinyl alcohol include polyvinyl formal, polyvinyl acetal, and the like, olefins such as ethylene and propylene, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid, and their alkyl esters and acrylamide. Things. Polyvinyl alcohol having a polymerization degree of about 1000 to 10,000 and a saponification degree of about 80 to 100 mol% is generally used.

The polyvinyl alcohol film may contain an additive such as a plasticizer. Examples of the plasticizer include polyols and condensates thereof, and examples thereof include glycerin, diglycerin, triglycerin, ethylene glycol, propylene glycol, and polyethylene glycol. The amount of the plasticizer used is not particularly limited, but is preferably 20% by weight or less in the polyvinyl alcohol film.

The polyvinyl alcohol film (unstretched film) is at least subjected to uniaxial stretching treatment and iodine dyeing treatment according to a conventional method. Furthermore, boric acid treatment and iodine ion treatment can be performed. Moreover, the polyvinyl alcohol film (stretched film) subjected to the treatment is dried according to a conventional method to form a polarizer.

Arbitrary appropriate thickness can be employ | adopted as thickness of the polarizer (P) used for the polarizing plate of this invention. The thickness of the polarizer is typically 5 to 80 μm, preferably 10 to 50 μm, and more preferably 20 to 40 μm. If it is said range, it is excellent in an optical characteristic and mechanical strength.

[Transparent protective film]
As a material constituting the transparent protective film, for example, a thermoplastic resin excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy and the like is used. Specific examples of such thermoplastic resins include cellulose resins such as triacetyl cellulose, polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth) acrylic resins, cyclic Examples thereof include polyolefin resins (norbornene resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof.

The transparent protective film may contain one or more arbitrary appropriate additives. Examples of the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a release agent, a coloring inhibitor, a flame retardant, a nucleating agent, an antistatic agent, a pigment, and a coloring agent. The content of the thermoplastic resin in the transparent protective film is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, still more preferably 60 to 98% by weight, and particularly preferably 70 to 97% by weight. . When content of the said thermoplastic resin in a transparent protective film is 50 weight% or less, there exists a possibility that the high transparency etc. which a thermoplastic resin originally has cannot fully be expressed.

The thickness of the transparent protective film can be appropriately determined, but is generally about 1 to 500 μm from the viewpoints of workability such as strength and handleability, and thin layer properties. In particular, it is preferably 1 to 300 μm, more preferably 5 to 200 μm, and further preferably 5 to 150 μm, particularly 20 to 100 μm.

As the transparent protective film of the present invention, it is preferable to use at least one selected from polyester resin, cellulose resin, polycarbonate resin, cyclic polyolefin resin and (meth) acrylic resin.

The polyester resin is not particularly limited. For example, terephthalic acid, isophthalic acid, orthophthalic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid Diphenylcarboxylic acid, diphenoxyethanedicarboxylic acid, diphenylsulfonecarboxylic acid, anthracene dicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, hexahydroterephthalic acid, Hexahydroisophthalic acid, malonic acid, dimethylmalonic acid, succinic acid, 3,3-diethylsuccinic acid, glutaric acid, 2,2-dimethylglutaric acid, adipic acid, 2-methyladipic acid, trimethyladipic acid, pimelic acid, Aze Dicarboxylic acids such as inic acid, dimer acid, sebacic acid, suberic acid, dodecadicarboxylic acid, ethylene glycol, propylene glycol, hexamethylene glycol, neopentyl glycol, 1,2-cyclohexanedimethanol, 1,4-cyclohexanedimethanol , Decamethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexadiol, 2,2-bis (4-hydroxyphenyl) propane, bis (4- (Hydroxyphenyl) sulfone or other diol, a homopolymer obtained by polycondensation of one kind each, a copolymer obtained by polycondensation of one or more dicarboxylic acids and two or more diols, or two or more dicarboxylic acids and a diol A copolymer obtained by polycondensation of one or more of these, and these It can include any of the blend resin obtained by blending two or more of the homopolymers and copolymers. Of these, polyethylene terephthalate resin is preferably used.

Cellulose resin is an ester of cellulose and fatty acid. Specific examples of such cellulose ester resins include triacetyl cellulose, diacetyl cellulose, tripropionyl cellulose, dipropionyl cellulose and the like. Among these, triacetyl cellulose is particularly preferable. Many products of triacetylcellulose are commercially available, which is advantageous in terms of availability and cost. Examples of commercially available products of triacetyl cellulose include the product names “UV-50”, “UV-80”, “SH-80”, “TD-80U”, “TD-TAC”, “UZ” manufactured by Fujifilm Corporation. -TAC "and" KC series "manufactured by Konica. In general, these triacetyl celluloses have an in-plane retardation (Re) of almost zero, but a thickness direction retardation (Rth) of about 60 nm.

A specific example of the cyclic polyolefin resin is preferably a norbornene resin. The cyclic olefin-based resin is a general term for resins that are polymerized using a cyclic olefin as a polymerization unit, and is described in, for example, JP-A-1-240517, JP-A-3-14882, JP-A-3-122137, and the like. Resin. Specific examples include cyclic olefin ring-opening (co) polymers, cyclic olefin addition polymers, cyclic olefins and α-olefins such as ethylene and propylene (typically random copolymers), And graft polymers obtained by modifying them with an unsaturated carboxylic acid or a derivative thereof, and hydrides thereof. Specific examples of the cyclic olefin include norbornene monomers.

Various products are commercially available as cyclic polyolefin resins. As specific examples, trade names “ZEONEX” and “ZEONOR” manufactured by ZEON CORPORATION, product names “ARTON” manufactured by JSR Corporation, “TOPAS” manufactured by TICONA, and product names manufactured by Mitsui Chemicals, Inc. “APEL”.

As the (meth) acrylic resin, Tg (glass transition temperature) is preferably 115 ° C. or higher, more preferably 120 ° C. or higher, still more preferably 125 ° C. or higher, and particularly preferably 130 ° C. or higher. When Tg is 115 ° C. or higher, the polarizing plate can be excellent in durability. Although the upper limit of Tg of the (meth) acrylic resin is not particularly limited, it is preferably 170 ° C. or lower from the viewpoint of moldability and the like. From the (meth) acrylic resin, a film having in-plane retardation (Re) and thickness direction retardation (Rth) of almost zero can be obtained.

As the (meth) acrylic resin, any appropriate (meth) acrylic resin can be adopted as long as the effects of the present invention are not impaired. For example, poly (meth) acrylic acid ester such as polymethyl methacrylate, methyl methacrylate- (meth) acrylic acid copolymer, methyl methacrylate- (meth) acrylic acid ester copolymer, methyl methacrylate-acrylic acid ester- (Meth) acrylic acid copolymer, (meth) methyl acrylate-styrene copolymer (MS resin, etc.), a polymer having an alicyclic hydrocarbon group (for example, methyl methacrylate-cyclohexyl methacrylate copolymer, Methyl methacrylate- (meth) acrylate norbornyl copolymer, etc.). Preferable examples include C1-6 alkyl poly (meth) acrylates such as polymethyl (meth) acrylate. More preferred is a methyl methacrylate resin containing methyl methacrylate as a main component (50 to 100% by weight, preferably 70 to 100% by weight).

Specific examples of the (meth) acrylic resin include, for example, (Meth) acrylic resin having a ring structure in the molecule described in Acrypet VH and Acrypet VRL20A manufactured by Mitsubishi Rayon Co., Ltd., and JP-A-2004-70296. And a high Tg (meth) acrylic resin system obtained by intramolecular crosslinking or intramolecular cyclization reaction.

As the (meth) acrylic resin, a (meth) acrylic resin having a lactone ring structure can also be used. Examples of the (meth) acrylic resin having a lactone ring structure include JP 2000-230016, JP 2001-151814, JP 2002-120326, JP 2002-254544, and JP 2005. No. 146084 and the like.

As the (meth) acrylic resin, an acrylic resin having a structural unit of unsaturated carboxylic acid alkyl ester and a structural unit of glutaric anhydride can be used. Examples of the acrylic resin include Japanese Patent Application Laid-Open Nos. 2004-70290, 2004-70296, 2004-163924, 2004-292812, 2005-314534, and 2006-. Examples described in JP-A-131898, JP-A-2006-206881, JP-A-2006-265532, JP-A-2006-283013, JP-A-2006-299905, and JP-A-2006-335902 are listed. It is done.

Further, as the (meth) acrylic resin, a thermoplastic resin having a glutarimide unit, a (meth) acrylic acid ester unit, and an aromatic vinyl unit can be used. Examples of the thermoplastic resin include JP-A-2006-309033, JP-A-2006-317560, JP-A-2006-328329, JP-A-2006-328334, JP-A-2006-337491, and JP-A-2006. -337374, JP-A 2006-337493, JP-A 2006-337569, and the like.

(Phase difference value of transparent protective film)
As the transparent protective film (E), a film having a small front refraction of less than 40 nm and a thickness direction retardation of less than 80 nm can be used as having a small birefringence and not converting the polarization state. As such a transparent protective film having a small birefringence, an unstretched film can be exemplified.

[Adhesive layer]
The transparent protective film (E) and the polarizer (P) are laminated via the adhesive layer (G). At this time, it is desirable to laminate both of them with an adhesive layer without an air gap. The adhesive layer (G) is formed of an adhesive (G ′). The kind in particular of adhesive (G ') is not restrict | limited, A various thing can be used.

The adhesive layer (G) used for bonding the polarizer (P) and the transparent protective film (E) is not particularly limited as long as it is optically transparent, and is water-based, solvent-based, hot-melt-based, or radical-curable. Although various forms are used, a water-based adhesive or a radical curable adhesive is preferable.

The water-based adhesive forming the adhesive layer (G) is not particularly limited, and examples thereof include vinyl polymer-based, gelatin-based, vinyl-based latex-based, polyurethane-based, isocyanate-based, polyester-based, and epoxy-based materials. It can be illustrated. Such an adhesive layer composed of an aqueous adhesive can be formed as an aqueous solution coating / drying layer, etc., but when preparing the aqueous solution, a catalyst such as a crosslinking agent, other additives, and an acid can be used as necessary. Can be blended. As the water-based adhesive, an adhesive containing a vinyl polymer is preferably used, and the vinyl polymer is preferably a polyvinyl alcohol resin. The polyvinyl alcohol-based resin can contain a water-soluble crosslinking agent such as boric acid, borax, glutaraldehyde, melamine, or oxalic acid. In particular, when a polyvinyl alcohol polymer film is used as the polarizer, it is preferable from the viewpoint of adhesiveness to use an adhesive containing a polyvinyl alcohol resin. Furthermore, an adhesive containing a polyvinyl alcohol-based resin having an acetoacetyl group is more preferable from the viewpoint of improving durability.

Polyvinyl alcohol resin is polyvinyl alcohol obtained by saponifying polyvinyl acetate; a derivative thereof; a saponified product of a copolymer of vinyl acetate and a monomer having copolymerizability; Examples thereof include modified polyvinyl alcohols that have been converted into ethers, ethers, grafts, or phosphoric esters. Examples of the monomer include unsaturated carboxylic acids such as (anhydrous) maleic acid, fumaric acid, crotonic acid, itaconic acid, (meth) acrylic acid, and esters thereof; α-olefins such as ethylene and propylene; (meth) Examples include allyl sulfonic acid (soda), sulfonic acid soda (monoalkylmalate), disulfonic acid soda alkylmalate, N-methylolacrylamide, acrylamide alkylsulfonic acid alkali salt, N-vinylpyrrolidone, and N-vinylpyrrolidone derivatives. . These polyvinyl alcohol resins can be used singly or in combination of two or more.

The polyvinyl alcohol resin is not particularly limited, but from the viewpoint of adhesiveness, the average degree of polymerization is about 100 to 5000, preferably 1000 to 4000, and the average saponification degree is about 85 to 100 mol%, preferably 90 to 100 mol%. It is.

A polyvinyl alcohol-based resin containing an acetoacetyl group is obtained by reacting a polyvinyl alcohol-based resin with diketene by a known method. For example, a method in which a polyvinyl alcohol resin is dispersed in a solvent such as acetic acid and diketene is added thereto, and a polyvinyl alcohol resin is previously dissolved in a solvent such as dimethylformamide or dioxane, and diketene is added thereto. And the like. Another example is a method in which diketene gas or liquid diketene is brought into direct contact with polyvinyl alcohol.

The degree of acetoacetyl group modification of the polyvinyl alcohol resin containing an acetoacetyl group is not particularly limited as long as it is 0.1 mol% or more. If it is less than 0.1 mol%, the water resistance of the adhesive layer is insufficient and unsuitable. The degree of acetoacetyl group modification is preferably about 0.1 to 40 mol%, more preferably 1 to 20 mol%, and particularly preferably 2 to 7 mol%. When the acetoacetyl group modification degree exceeds 40 mol%, the effect of improving water resistance is small. The degree of acetoacetyl modification is a value measured by NMR.

As the crosslinking agent, those used for polyvinyl alcohol-based adhesives can be used without particular limitation. The amount of the crosslinking agent can be appropriately designed according to the type of the polyvinyl alcohol resin, but is usually about 4 to 60 parts by weight, preferably 10 to 55 parts by weight with respect to 100 parts by weight of the polyvinyl alcohol resin. Degree, more preferably 20 to 50 parts by weight. In such a range, good adhesiveness can be obtained.

In order to improve the durability, a polyvinyl alcohol resin containing an acetoacetyl group is used. Also in this case, the crosslinking agent is used in the range of about 4 to 60 parts by weight, preferably about 10 to 55 parts by weight, more preferably 20 to 50 parts by weight, as described above, with respect to 100 parts by weight of the polyvinyl alcohol resin. Is preferred. When the amount of the crosslinking agent is too large, the reaction of the crosslinking agent proceeds in a short time and the adhesive tends to gel. As a result, the pot life as an adhesive is extremely shortened, making industrial use difficult. From this point of view, the blending amount of the crosslinking agent is used in the above blending amount. However, since the resin solution of the present invention contains the metal compound colloid, the blending amount of the crosslinking agent is large as described above. Even if it exists, it can be used with good stability.

As the adhesive, a resin solution containing a polyvinyl alcohol resin, a crosslinking agent, and a metal compound colloid having an average particle size of 1 to 100 nm is preferably used. The resin solution is usually used as an aqueous solution. The concentration of the resin solution is not particularly limited, but is 0.1 to 15% by weight, preferably 0.5 to 10% by weight in consideration of coating property and storage stability.

The viscosity of the resin solution as the adhesive is not particularly limited, but a resin solution in the range of 1 to 50 mPa · s is used. The nick generated in the production of the polarizing plate tends to increase as the viscosity of the resin solution decreases. However, according to the polarizing plate adhesive of the present invention, the nick has a range of 1 to 20 mPa · s. Even in the low viscosity range, the occurrence of nicks can be suppressed, and the occurrence of nicks can be suppressed regardless of the viscosity of the resin solution. A polyvinyl alcohol resin containing an acetoacetyl group cannot be increased in polymerization degree compared to a general polyvinyl alcohol resin and has been used at a low viscosity as described above. Even when a polyvinyl alcohol-based resin containing an acetyl group is used, the occurrence of nicks caused by the low viscosity of the resin solution can be suppressed.

When the adhesive layer (G1) is formed of an aqueous adhesive or the like, the thickness of the adhesive layer (G1) is about 10 to 300 nm. The thickness of the adhesive layer is more preferably 10 to 200 nm, more preferably 20 to 150 nm, from the viewpoint of obtaining a uniform in-plane thickness and sufficient adhesive strength.

After applying the water-based adhesive, the polarizer (P) and the transparent protective film (E) are bonded together using a roll laminator or the like. Application | coating of the said adhesive agent may be performed to any of a transparent protective film and a polarizer, and may be performed to both. After the bonding, a drying process is performed to form an adhesive layer composed of a coating dry layer. The drying temperature is about 5 to 150 ° C., preferably 30 to 120 ° C., for 120 seconds or longer, and further for 300 seconds or longer.

Examples of the radical curable adhesive include various active energy ray curable types such as an electron beam curable type and an ultraviolet ray curable type, and a thermosetting type, but there are active energy ray curable types that can be cured in a short time. preferable. In particular, an electron beam curable type is preferable. An electron beam curable adhesive can be used. By using an electron beam for the adhesive curing method used to bond the polarizer and the transparent protective film (ie, dry lamination), a heating step such as an ultraviolet curing method becomes unnecessary, and the productivity is extremely high. can do.

On the other hand, when the adhesive layer (G1) is formed of a curable adhesive (electron beam curable adhesive), the thickness of the adhesive layer (G1) is preferably 0.1 to 20 μm, more preferably The thickness is preferably 0.2 to 10 μm, more preferably 0.3 to 8 μm. When the thickness is small, the cohesive force of the adhesive force itself cannot be obtained, and the adhesive strength may not be obtained. If the thickness of the adhesive layer (G1) exceeds 20 μm, the cost increases and the shrinkage of the adhesive itself is affected, which may adversely affect the optical properties of the polarizing plate.

[Adhesive layer]
An appropriate pressure-sensitive adhesive can be used for forming the pressure-sensitive adhesive layer (B), and the type thereof is not particularly limited. Adhesives include rubber adhesives, acrylic adhesives, silicone adhesives, urethane adhesives, vinyl alkyl ether adhesives, polyvinyl alcohol adhesives, polyvinyl pyrrolidone adhesives, polyacrylamide adhesives, Examples thereof include cellulose-based pressure-sensitive adhesives.

Among these pressure-sensitive adhesives, those having excellent optical transparency, suitable wettability, cohesiveness, and adhesive pressure characteristics, and excellent weather resistance and heat resistance are preferably used. An acrylic pressure-sensitive adhesive is preferably used as one exhibiting such characteristics.

The pressure-sensitive adhesive layer (B) is usually provided by applying a solution of the pressure-sensitive adhesive on a release sheet and drying. The pressure-sensitive adhesive solution is prepared, for example, as a solution of about 10 to 40% by weight in which the composition is dissolved or dispersed in a solvent composed of a single solvent or a mixture of appropriate solvents such as toluene and ethyl acetate. As a coating method, a roll coating method such as reverse coating or gravure coating, a spin coating method, a screen coating method, a fountain coating method, a dipping method, or a spray method can be adopted. The release sheet provided with the pressure-sensitive adhesive layer (B) is used by a method of transferring the release sheet. Moreover, an adhesion layer (B) can be formed as a coating film by apply | coating the said adhesive to the protective layer (H) provided in the one side of polarizer (P).

The thickness of the pressure-sensitive adhesive layer (B) is usually about 3 to 100 μm, preferably 5 to 50 μm, and more preferably 10 to 40 μm.

As a constituent material of the release sheet, paper, polyethylene, polypropylene, polyethylene terephthalate and other synthetic resin films, rubber sheets, paper, cloth, non-woven fabric, nets, foam sheets and metal foils, and appropriate thin leaf bodies such as laminates thereof Etc. In order to improve the peelability from the pressure-sensitive adhesive layer, the surface of the release sheet may be subjected to a low-adhesive release treatment such as silicone treatment, long-chain alkyl treatment, and fluorine treatment as necessary.

[Protective layer]
The protective layer (H) is provided between the polarizer (P) and the pressure-sensitive adhesive layer (B). The protective layer (H) has a tensile modulus of 100 MPa or more. The protective layer (H) of the present invention has a tensile elastic modulus of 100 MPa or more, so that the polarizer (P) is externally exposed to humidification / drying, heating / cooling, and mechanical tension, compression, bending, and the like. Suppresses expansion and contraction due to stress and suppresses the occurrence of polarizer cracks. Cracks generated in the polarizer (P) are mainly caused by a dimensional change in the contraction direction of the polarizer (P), and the mechanical holding ability of the protective layer (H) is the tensile force of the protective layer (H). The higher the modulus of elasticity, the greater the effect of suppressing polarizer cracks. In addition, a tensile elasticity modulus is a value measured based on description of an Example. The tensile elastic modulus of the protective layer (H) is preferably 100 MPa or more, further 150 MPa or more, more preferably 500 MPa or more, and further preferably 1000 MPa or more from the viewpoint of durability. On the other hand, the tensile modulus is preferably 50000 MPa or less, more preferably 30000 MPa or less, and further preferably 20000 MPa or less. If the tensile modulus is too high, cracking may occur due to the influence of bending stress or the like.

As the protective layer forming agent (H ′) for forming the protective layer (H), for example, a cyanoacrylate-based forming agent, an epoxy-based forming agent, an isocyanate-based forming agent, or an acrylic-based forming agent is used. When these protective layer forming agents (H ′) are used, the tensile elastic modulus is preferably 100 to 2000 MPa, more preferably 150 to 1000 MPa, and further preferably 500 to 1000 MPa from the viewpoint of durability and the like. .

Examples of cyanoacrylate-based forming agents include alkyl-α-cyanoacrylates such as methyl-α-cyanoacrylate, ethyl-α-cyanoacrylate, butyl-α-cyanoacrylate, octyl-α-cyanoacrylate, and cyclohexyl-α-. And cyanoacrylate and methoxy-α-cyanoacrylate. As the cyanoacrylate-based forming agent, for example, those used as a cyanoacrylate-based adhesive can be used.

The epoxy-based forming agent contains an epoxy resin and its curing agent. As an epoxy-type formation agent, what is used as an epoxy-type adhesive agent can be used, for example. The epoxy type forming agent can be used as a one-component type containing an epoxy resin and its curing agent, but is usually used as a two-component type in which a curing agent is added to the epoxy resin. . The epoxy-based forming agent is usually used as a solution. The solution may be a solvent system or an aqueous system such as an emulsion, a colloidal dispersion, or an aqueous solution.

Examples of the epoxy resin include various compounds containing two or more epoxy groups in the molecule. For example, bisphenol type epoxy resin, aliphatic type epoxy resin, aromatic type epoxy resin, halogenated bisphenol type epoxy resin, biphenyl And epoxy resin. Moreover, although an epoxy resin can be suitably determined according to an epoxy equivalent and the number of functional groups, the epoxy equivalent of 500 or less is used suitably from a durable viewpoint.

The curing agent for the epoxy resin is not particularly limited, and various types such as phenol resin type, acid anhydride type, carboxylic acid type, and polyamine type can be used. As the phenol resin-based curing agent, for example, phenol novolak resin, bisphenol novolak resin, xylylene phenol resin, cresol novolak resin, or the like is used. Examples of acid anhydride-based curing agents include: maleic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, succinic anhydride, and the like. Examples of carboxylic acid-based curing agents include carboxylic acids such as pyromellitic acid and trimellitic acid. Examples thereof include block carboxylic acids added with acids and vinyl ether. Moreover, as an epoxy-type two liquid formation agent, what consists of two liquids of an epoxy resin and polythiol, what consists of two liquids of an epoxy resin and polyamide, etc. can be used, for example.

The blending amount of the curing agent varies depending on the equivalent to the epoxy resin, but is preferably 30 to 70 parts by weight, more preferably 40 to 60 parts by weight with respect to 100 parts by weight of the epoxy resin.

Furthermore, in addition to the epoxy resin and its curing agent, various curing accelerators can be used as the epoxy-based forming agent. Examples of the curing accelerator include various imidazole compounds and derivatives thereof, dicyandiamide, and the like.

Among the epoxy-based forming agents, in the present invention, it is preferable to use a two-component curable epoxy resin, in which the epoxy resin component is a bisphenol A type epoxy resin and the curing agent component is an amine-based material, especially a cyclic amine. preferable. Furthermore, it is preferable that an anionic curing accelerator is added to any one of the above components. Examples of anionic curing accelerators include aromatic tertiary amine compounds, lactone compounds, 1,2,6-hexanetriol, N, N-dicyclohexylcarbodiimide, succinic acid amide and the like.

Examples of the isocyanate-based forming agent include those used as a crosslinking agent in the formation of the pressure-sensitive adhesive layer (B). As the isocyanate-based crosslinking agent, a compound having at least two isocyanate groups can be used. For example, the polyisocyanate compound can be used as an isocyanate-based forming agent. Specifically, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene diisocyanate, 1,3-bisisocyanatomethylcyclohexane, hexamethylene diisocyanate, tetramethylxylylene diisocyanate, m-isopropenyl-α, α-dimethylbenzyl isocyanate, methylene bis 4-phenyl isocyanate, p-phenylene diisocyanate or their dimers, trimers such as isocyanuric acid tris (6-inocyanate hexyl), biuret, trimethylolpropane, etc. Examples include those reacted with polyhydric alcohols and polyhydric amines. As the isocyanate-based crosslinking agent, those having three or more isocyanate groups such as isocyanuric acid tris (6-inocyanate hexyl) are preferable. As an isocyanate type formation agent, what is used as an isocyanate type adhesive agent is mention | raise | lifted, for example.

Among the isocyanate-based forming agents, in the present invention, it is preferable to use those having a rigid structure in which a cyclic structure (benzene ring, cyanurate ring, isocyanurate ring, etc.) accounts for a large proportion in the structure. As the isocyanate forming agent, for example, trimethylolpropane-tri-tolylene isocyanate, tris (hexamethylene isocyanate) isocyanurate and the like are preferably used.

In addition, the said isocyanate type crosslinking agent can also use what provided the protective group to the terminal isocyanate group. Protecting groups include oximes and lactams. In the case where the isocyanate group is protected, the protecting group is dissociated from the isocyanate group by heating, and the isocyanate group reacts.

Further, a reaction catalyst can be used to increase the reactivity of the isocyanate group. The reaction catalyst is not particularly limited, but a tin-based catalyst or an amine-based catalyst is suitable. The reaction catalyst can use 1 type (s) or 2 or more types. The amount of the reaction catalyst used is usually 5 parts by weight or less with respect to 100 parts by weight of the isocyanate-based crosslinking agent. When the amount of the reaction catalyst is large, the crosslinking reaction rate increases and foaming of the forming agent occurs. Even if the forming agent after foaming is used, sufficient adhesion cannot be obtained. Usually, when a reaction catalyst is used, it is preferably 0.01 to 5 parts by weight, more preferably 0.05 to 4 parts by weight.

As the tin-based catalyst, both inorganic and organic catalysts can be used, but an organic catalyst is preferred. Examples of the inorganic tin-based catalyst include stannous chloride and stannic chloride. The organic tin-based catalyst is preferably one having at least one organic group such as an aliphatic group or alicyclic group having a skeleton such as a methyl group, an ethyl group, an ether group or an ester group. Examples include tetra-n-butyltin, tri-n-butyltin acetate, n-butyltin trichloride, trimethyltin hydroxide, dimethyltin dichloride, dibutyltin dilaurate and the like.

The amine catalyst is not particularly limited. For example, those having at least one organic group such as an alicyclic group such as quinoclidine, amidine, and diazabicycloundecene are preferable. In addition, examples of the amine catalyst include triethylamine. Examples of reaction catalysts other than the above include cobalt naphthenate and benzyltrimethylammonium hydroxide.

The isocyanate-based forming agent is usually used as a solution. The solution may be a solvent system or an aqueous system such as an emulsion, a colloidal dispersion, or an aqueous solution. The organic solvent is not particularly limited as long as the components constituting the forming agent are uniformly dissolved. Examples of the organic solvent include toluene, methyl ethyl ketone, ethyl acetate and the like. In the case of using an aqueous system, for example, alcohols such as n-butyl alcohol and isopropyl alcohol and ketones such as acetone can be blended. In the case of using an aqueous system, a dispersant is used, or an isocyanate-based crosslinking agent, a functional group having low reactivity with an isocyanate group such as a carboxylate, a sulfonate, or a quaternary ammonium salt, or an aqueous dispersion such as polyethylene glycol. It can carry out by introduce | transducing a sex component.

Examples of the acrylic forming agent include curable components such as monomers and / or oligomer components that undergo radical polymerization by active energy rays or heat.

The monomer and / or oligomer component that undergoes radical polymerization includes a monomer and / or oligomer component having an unsaturated double bond such as a (meth) acryloyl group or vinyl group, and the (meth) acryloyl group is particularly advantageous because of its excellent reactivity. Monomer and / or oligomer components having the following are preferably used.

Specific examples of the monomer component having a (meth) acryloyl group include those usually used for monomers constituting acrylic polymers.

In addition, as a monomer and / or oligomer component that undergoes radical polymerization, two or more unsaturated double bonds such as a (meth) acryloyl group and a vinyl group are present as a functional group similar to the monomer component in a skeleton such as polyester, epoxy, and urethane. Added polyester (meth) acrylate, epoxy (meth) acrylate, urethane (meth) acrylate, and the like are used. The unsaturated double bond is preferably 2 or more, preferably 4 or more, and more preferably 6 or more.

Specific examples of the monomer and / or oligomer component having a (meth) acryloyl group include tripropylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, Bisphenol A diglycidyl ether di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol (Meth) acrylates such as penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate Esters of an acid and a polyhydric alcohol, and the like.

In addition to the above, monomers and / or oligomer components that undergo radical polymerization include 2-propenyl-di-3-butenyl cyanurate, 2-hydroxyethylbis (2-acryloxyethyl) cyanurate, and tris (2-acryloxyethyl). ) Cyanurates or isocyanurate compounds such as isocyanurate and tris (2-methacryloxyethyl) isocyanurate.

As the protective layer forming agent (H ′), among the acrylic forming agents, it is preferable to use an active energy ray curable forming agent containing a curable component that is cured by active energy rays. The active energy ray curable forming agent has a very good productivity because the thermosetting type forming agent (epoxy type, isocyanate type, acrylic type) takes a long time to react. preferable. In addition, when the thermosetting type forming agent is applied to the polarizer (P), the property of the polarizer (P) is lowered by heating for reaction, but with the active energy ray curable type forming agent, This is also preferable in that it is not affected by heat. In addition, in the moisture curing type forming agent (cyanoacrylate type), the polarizer (P) is a polyvinyl alcohol type material, so that the polarizer characteristics change due to moisture. It is also preferable from the point of no. Examples of the curable component include a compound having a (meth) acryloyl group and a compound having a vinyl group (monomer and / or oligomer). These curable components may be monofunctional or bifunctional or higher. These curable components can be used alone or in combination of two or more so that the protective layer (H) formed by the curable component satisfies a tensile elastic modulus of 100 MPa or more. As these curable components, compounds having a (meth) acryloyl group are suitable. As the compound having a (meth) acryloyl group, an N-substituted amide monomer is preferably used. These monomers are preferable in terms of durability. When these protective layer forming agents (H ′) are used, the tensile elastic modulus is 100 to 50000 MPa, more preferably 150 to 30000 MPa, further 500 to 30000 MPa, and further 1000 to 1000 from the viewpoint of durability and the like. It is preferably 20000 MPa. As the active energy ray curable forming agent, an active energy ray curable adhesive can be used.

The N-substituted amide monomer is represented by the general formula (1): CH ₂ ═C (R ¹ ) —CONR ² (R ³ ) (R ¹ represents a hydrogen atom or a methyl group, R ² represents a hydrogen atom or a hydroxyl group, mercapto Represents a linear or branched alkyl group having 1 to 4 carbon atoms which may have a group, an amino group or a quaternary ammonium group, and R ³ represents a hydrogen atom or a linear or branched chain having 1 to 4 carbon atoms Wherein R ² and R ³ are simultaneously a hydrogen atom, or R ² and R ³ are bonded to form a 5-membered ring or a 6-membered ring that may contain an oxygen atom. It is expressed by Examples of the linear or branched alkyl group having 1 to 4 carbon atoms for R ² or R ³ in the general formula (1) include a methyl group, an ethyl group, an isopropyl group, and a t-butyl group. Examples of the alkyl group having a hydroxyl group include a hydroxymethyl group and a hydroxyethyl group, and examples of the alkyl group having an amino group include an aminomethyl group and an aminoethyl group. Moreover, when R < ² >, R < ³ > couple | bonds together and forms the 5-membered ring or 6-membered ring which may contain an oxygen atom, it has a heterocyclic ring which has nitrogen. Examples of the heterocyclic ring include morpholine ring, piperidine ring, pyrrolidine ring, piperazine ring and the like.

Specific examples of the N-substituted amide monomer include, for example, N-methyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropylacrylamide, N- Butyl (meth) acrylamide, N-hexyl (meth) acrylamide, N-methylol (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, N-methylol-N-propane (meth) acrylamide, aminomethyl (meth) acrylamide, Examples include aminoethyl (meth) acrylamide, mercaptomethyl (meth) acrylamide, and mercaapethyl (meth) acrylamide. Examples of the heterocyclic-containing monomer having a heterocyclic ring include N-acryloylmorpholine, N-acryloylpiperidine, N-methacryloylpiperidine, N-acryloylpyrrolidine and the like. These N-substituted amide monomers can be used alone or in combination of two or more.

As the N-substituted amide monomer, N-hydroxyethylacrylamide, N-methylolacrylamide, N-isopropylacrylamide, and N-acryloylmorpholine are preferable. The N-substituted amide monomer exhibits good durability even with respect to a polarizer having a low moisture content or a transparent protective film using a material with low moisture permeability. However, the above exemplified monomers are particularly good. Shows durability. Of these, N-hydroxyethylacrylamide is preferred.

The N-substituted amide monomers can be used singly or in combination of two or more. When two or more of them are combined, N-hydroxyethylacrylamide and N are used from the viewpoint of durability and adhesiveness. A combination of acryloylmorpholine is preferred. In the case of the combination, the ratio of N-hydroxyethylacrylamide to the total amount of N-hydroxyethylacrylamide and N-acryloylmorpholine is preferably 40% by weight or more in order to obtain good adhesiveness. The proportion is more preferably 40 to 90% by weight, and further preferably 60 to 90% by weight.

Moreover, as said curable component, in addition to the above, as a compound having a (meth) acryloyl group, for example, various epoxy (meth) acrylates, urethane (meth) acrylates, polyester (meth) acrylates, various ( And (meth) acrylate monomers. Among these, epoxy (meth) acrylates, particularly monofunctional (meth) acrylates having an aromatic ring and a hydroxy group are preferably used. These curable components are used alone and in combination with the N-substituted amide monomer when a protective layer (H) having a tensile elastic modulus of 100 MPa or more cannot be formed.

As the monofunctional (meth) acrylate having an aromatic ring and a hydroxy group, various monofunctional (meth) acrylates having an aromatic ring and a hydroxy group can be used. The hydroxy group may exist as a substituent of the aromatic ring, but in the present invention, it exists as an organic group (bonded to a hydrocarbon group, particularly an alkylene group) that bonds the aromatic ring and the (meth) acrylate. Those that do are preferred.

Examples of the monofunctional (meth) acrylate having an aromatic ring and a hydroxy group include a reaction product of a monofunctional epoxy compound having an aromatic ring and (meth) acrylic acid. Examples of the monofunctional epoxy compound having an aromatic ring include phenyl glycidyl ether, t-butylphenyl glycidyl ether, and phenyl polyethylene glycol glycidyl ether. Specific examples of the monofunctional (meth) acrylate having an aromatic ring and a hydroxy group include, for example, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2-hydroxy-3-t-butylphenoxypropyl (meth) Acrylate, 2-hydroxy-3-phenyl polyethylene glycol propyl (meth) acrylate and the like.

Further, examples of the compound having a (meth) acryloyl group include a carboxyl group monomer. A carboxyl group monomer is also preferable in terms of adhesiveness. Examples of the carboxyl group monomer include (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, and the like. Of these, acrylic acid is preferred.

The active energy ray-curable forming agent contains a curable component, but in addition to the component, if necessary, an additive may be added appropriately. The active energy ray curable forming agent can be used in an electron beam curable type or an ultraviolet curable type. When the forming agent is used as an electron beam curable type, it is not particularly necessary that the forming agent contains a photopolymerization initiator, but when used as an ultraviolet curable type, a photopolymerization initiator is used. . The amount of the photopolymerization initiator used is usually about 0.1 to 10 parts by weight, preferably 0.5 to 3 parts by weight per 100 parts by weight of the curable component.

The protective layer forming agent (H ′) further includes a coupling agent such as a silane coupling agent and a titanium coupling agent, various tackifiers, an ultraviolet absorber, an antioxidant, a heat stabilizer, and hydrolysis resistance. Stabilizers such as stabilizers can also be blended. These stabilizers and the like can be blended in the adhesive (G ′) as well.

The protective layer (H) is formed by the protective layer forming agent (H ′). The protective layer (H) is usually formed on the polarizer (P). The thickness of the protective layer (H) is about 0.01 to 30 μm, preferably 0.05 to 15 μm, and more preferably 0.1 to 7.5 μm. As the protective layer forming agent (H ′), for example, when a cyanoacrylate-based forming agent, an epoxy-based forming agent, or an isocyanate-based forming agent is used, the thickness of the protective layer (H) is 0. The thickness is preferably 01 to 5 μm, more preferably 0.05 to 3 μm. The thickness of the protective layer (H) is preferably adjusted to the above range from the viewpoint of uniformly forming a coating film and affecting the optical properties.

The protective layer (H) preferably satisfies the photoelastic coefficient (m ² / N) × thickness (m) ≦ 1 × 10 ⁻¹⁴ (m ² / N). The photoelastic coefficient is measured according to the following.
<Photoelastic coefficient>
Using an ellipsometer (M220) manufactured by JASCO Corporation, the stress refractive index when a stress of 1 × 10 ⁻⁶ to 30 × 10 ⁻⁶ is applied to an optical film having a width of 2 cm at room temperature (23 ° C.) These were measured and plotted, and c: photoelastic coefficient (m ² / N) was calculated from stress birefringence Δn = cδ. Where δ is stress (N / m ² ).

The object of the present invention is to prevent the polarizer (P) from being cracked by the protective layer (H) formed on the surface of the polarizer (P). This is caused by expansion and contraction of the film due to drying, heating, and the like. Thus, when expansion and contraction occurs in the polarizer (P), the force acts on the transparent protective film (E) and the protective layer (H) disposed on the surface of the polarizer (P). This stress induces birefringence. In the present invention, the protective layer (H) formed on the surface of the polarizer (P) is used by being disposed on the liquid crystal cell side with respect to the polarizer (P). Therefore, the influence on the display of the image display apparatus may become serious. More specifically, the generated birefringence becomes a phase difference, particularly light in black display, and the contrast ratio is lowered, and the distribution is recognized as display unevenness. At this time, the photoelastic coefficient is used as an index of the ease of occurrence of birefringence due to stress. When this photoelastic coefficient is large, birefringence is likely to occur with a smaller stress. Further, when the thickness of the protective layer (H) is thick, the birefringence increases. The magnitude of the phase difference due to the generated birefringence is expressed by phase difference = photoelastic coefficient × stress × thickness. When birefringence occurs in the plane, the polarization state of polarized light changes due to the influence of the phase difference. In a liquid crystal display using polarized light, there is an influence such as in-plane transmittance unevenness. For this reason, a material having a photoelastic coefficient as small as possible is preferred in order to reduce the occurrence of birefringence due to the influence of contraction and expansion of the constituent members. Further, a thinner protective layer (H) is preferred because the influence of birefringence is reduced. As described above, the thickness of the protective layer (H) is preferably 30 μm or less, more preferably 15 μm or less, and even more preferably 7.5 μm or less.

The formation of the protective layer (H) can be appropriately selected depending on the kind of the protective layer forming agent (H ′), but is usually about 30 to 100 ° C., preferably 50 to 80 ° C. It is performed by drying for about 5 to 15 minutes. In the case of a cyanoacrylate-based forming agent, since the curing is fast, the protective layer (H) can be formed in a time shorter than the above time.

In the pressure-sensitive adhesive polarizing plate of the present invention, the polarizer (P) and the pressure-sensitive adhesive layer (B) are laminated via the protective layer (H). ) By adhering a protective layer (H) and an adhesive layer (B) provided on one side. In this case, the pressure-sensitive adhesive layer (B) usually used is provided on the release sheet. Moreover, the said lamination | stacking can be performed by apply | coating an adhesive to the protective layer (H) provided in the one side of polarizer (P), and forming an adhesive layer (B) as a coating film.

The formation of the protective layer (H) on the polarizer (P) and the bonding of the protective layer (H) and the pressure-sensitive adhesive layer (B) are preferably performed continuously. Moreover, it is preferable to also perform continuously bonding by the adhesive bond layer (G) of the said polarizer (P) and a transparent protective film (E). Moreover, the said bonding can also be performed continuously from manufacture of a polarizer.

[Other optical layers]
(Formation of surface treatment layer)
In the pressure-sensitive adhesive polarizing plate of the present invention, an optional optical layer can be added to the transparent protective film (E) on the side where the polarizer (P) is not bonded to the adhesive layer (G). As such an optical layer, a hard coat layer, an antireflection treatment, an anti-sticking treatment, or a treatment subjected to treatment for diffusion or anti-glare can be used.

The hard coat treatment is performed for the purpose of preventing scratches on the polarizing plate surface. For example, the above-mentioned transparent protective film is cured with excellent hardness and sliding properties by an appropriate ultraviolet curable resin such as acrylic or silicone. It can form by the system etc. which are added to the surface of a film (E). The antireflection treatment is performed for the purpose of preventing the reflection of external light on the surface of the polarizing plate, and can be achieved by forming an antireflection film or the like according to the prior art. In addition, the sticking prevention treatment is performed for the purpose of preventing adhesion with an adjacent layer (for example, a backlight-side diffusion plate).

The anti-glare treatment is applied for the purpose of preventing the outside light from being reflected on the surface of the polarizing plate and obstructing the visibility of the light transmitted through the polarizing plate. For example, the surface is roughened by a sandblasting method or an embossing method. It can be formed by imparting a fine concavo-convex structure to the surface of the transparent protective film (E) by an appropriate method such as a compounding method of transparent fine particles. Examples of the fine particles to be included in the formation of the surface fine concavo-convex structure include conductive materials made of silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide, and the like having an average particle diameter of 0.5 to 20 μm. In some cases, transparent fine particles such as inorganic fine particles, organic fine particles composed of a crosslinked or uncrosslinked polymer, and the like are used. In the case of forming a surface fine uneven structure, the amount of fine particles used is generally about 2 to 70 parts by weight, preferably 5 to 50 parts by weight, based on 100 parts by weight of the transparent resin forming the surface fine uneven structure. The antiglare layer may also serve as a diffusion layer (viewing angle expanding function or the like) for diffusing the light transmitted through the polarizing plate to expand the viewing angle or the like.

The antireflection layer, the antisticking layer, the diffusion layer, the antiglare layer, and the like can be provided on the transparent protective film (E), or can be provided separately as an optical layer.

Other examples of the optical layer that can be applied to the polarizing plate of the present invention include a brightness enhancement film, a reflective layer, a retardation plate, and the like.

[Image display device]
The pressure-sensitive adhesive polarizing plate of the present invention can be preferably used for forming an image display device such as a liquid crystal display device or an organic EL display device.

(Liquid crystal display device)
The liquid crystal display device can be formed according to the conventional method. That is, a liquid crystal display device generally has a liquid crystal cell, a polarizing plate, and, if necessary, appropriate elements such as a diffusion plate, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusion plate, a backlight, It is formed by arranging one or more parts at appropriate positions and incorporating a drive circuit. The formation of the liquid crystal display device is not particularly limited except that the pressure-sensitive adhesive polarizing plate according to the present invention is used, and can be based on the conventional one. As the liquid crystal cell, any type of liquid crystal cell such as a TN type, STN type, or π type can be used.

The adhesive polarizing plate of the present invention can be installed on one side or both sides of the liquid crystal cell. When providing an adhesive polarizing plate on both sides, they may be the same or different.

[Method for forming liquid crystal display device]
[Conventional Method for Forming Liquid Crystal Display]
By the way, in forming an image display device such as a liquid crystal display device or an organic EL display device, a transparent protective film (E) is laminated only on one side of the polarizer (P) like the pressure-sensitive adhesive polarizing plate of the present invention. In the case of a structure, the stress provided to the film interface of a polarizer (P) may differ in the main surface by which the transparent protective film (E) is laminated | stacked, and the other main surface. That is, since the layer structure is different between the front and back of the polarizer (P), the external stress applied to the polarizer may be different between the front and back of the film. Due to this difference in external stress, the film tends to have a curvature. Such a film that is easily bent is difficult to be processed into an image display device in the conventional manufacturing process as described below.

As shown conceptually in FIG. 2, the manufacturing process of a conventional image device is roughly divided into a manufacturing process in an optical film manufacturer and a manufacturing process in a panel processing manufacturer. First, an optical film manufacturer manufactures an optical film such as a polarizing plate as a roll material for a long (band-shaped) sheet product (# 1). Next, the original roll is slit to a predetermined size (a size according to the size of the optical display unit) (# 2). Next, the slit raw material is cut to a fixed length in accordance with the size of the optical display unit to be bonded, such as a liquid crystal cell or an organic EL panel (# 3). Next, an appearance inspection is performed on the sheet-like product (optical film) that has been cut into pieces (# 4). Examples of the inspection method include visual defect inspection and inspection using a known defect inspection apparatus. The defect means, for example, surface or internal dirt, scratches, a dent-like defect including a foreign object, an uneven defect, a bubble, a foreign object, or the like. Next, the finished product is inspected (# 5). The finished product inspection is an inspection in accordance with quality standards that are stricter than the appearance inspection. Next, the end surfaces of the four end surfaces of the sheet-like product are processed (# 6). This is performed to prevent the adhesive or the like from protruding from the end face during transportation. Next, in a clean room environment, the single sheet product is clean-wrapped (# 7). Next, packaging for transportation (transport packaging) (# 8). A sheet-like product is manufactured as described above and transported to a panel processing manufacturer.

The panel processing manufacturer packs and disassembles the sheet-like product that has been transported (# 11). Next, an appearance inspection is performed in order to inspect for scratches, dirt, etc. that occur during transportation or at the time of unpacking (# 12). The sheet-like product that has been determined to be non-defective in the inspection is conveyed to the next process. Note that this appearance inspection may be omitted. An optical display unit (for example, a liquid crystal cell which is a glass substrate unit in which a liquid crystal cell is sealed) to which a sheet-like product is bonded is manufactured in advance, and the optical display unit is washed before the bonding step ( # 13).

Next, the single sheet product and the optical display unit (liquid crystal cell) are bonded together (# 14). The release film is peeled off from the sheet-like product leaving a pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer is bonded to one surface of the optical display unit as a bonding surface. Further, it can be similarly bonded to the other surface of the optical display unit. In the case of bonding to both, an optical film having the same configuration may be bonded to each surface of the optical display unit, or an optical film having a different configuration may be bonded to each other. Next, the bonded state and defect inspection are performed (# 15). The optical display unit determined to be non-defective in this inspection is transported to the mounting process and mounted on the image display device (# 16). On the other hand, the optical display unit determined to be defective is subjected to a rework process (# 17). In the rework process, the optical film is peeled from the optical display unit. An optical film is newly bonded to the reworked optical display unit (# 14).

When the conventional manufacturing process as described above is applied to a film that is easily bent, a polarizing plate is present in a roll shape (# 1), (# 2), and is stretched between transport lines. Therefore, the bending behavior is suppressed by the tension. However, when this is cut to a fixed length (# 3), the tension that has suppressed the bending behavior of the polarizing plate is released, so that bending occurs, and appearance inspection (# 4) to bonding with the liquid crystal cell (# 14) ) Is difficult to handle. Furthermore, in the case of the conventional manufacturing process, in addition to the above-mentioned problem of handling due to the curvature, there is a problem that the manufacturing cost increases because it is a multi-process such as inspection and packing.

[Continuous manufacturing method]
The film formed in such a long roll shape is continuously bonded to the liquid crystal cell while being fed out in the presence of tension, so that the bending can be suppressed and this problem can be solved. In other words, by performing continuous cutting (# 3) and bonding to a liquid crystal cell (# 14), which were conventionally performed separately by an optical film manufacturer and a panel processing manufacturer, in one place, an appearance inspection (# 4). Finished product inspection (# 5), end face processing (# 6), clean packaging (# 7) transport packaging (# 8), packaging dismantling (# 11), appearance inspection (# 12) are not required, and curved The problem of handling due to can be solved.

Formation of such an image display device by a continuous method uses a roll original fabric preparation step of preparing the long sheet of the polarizing plate of the present invention as a roll original fabric, a sheet product from the roll original fabric, and a cutting means. A cutting step of cutting the polarizing plate into a predetermined size, and a bonding step of bonding the polarizing plate to the optical display unit through the adhesive layer after the cutting step.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to the examples shown below.

[Creating a polarizer]
A polyvinyl alcohol film having an average degree of polymerization of 2700 and a thickness of 75 μm was stretched and conveyed while being dyed between rolls having different peripheral speeds. First, it was immersed in a 30 ° C. water bath for 1 minute to swell the polyvinyl alcohol film and stretched 1.2 times in the conveying direction, and then a 30 ° C. potassium iodide concentration of 0.03% by weight and an iodine concentration of 0.3 By immersing in a weight% aqueous solution for 1 minute, the film was stretched 3 times in the transport direction with reference to a film (original length) that was not stretched at all while dyeing. Next, the film was stretched 6 times based on the original length in the conveying direction while being immersed in an aqueous solution having a boric acid concentration of 4% by weight and a potassium iodide concentration of 5% by weight for 30 seconds. Next, the obtained stretched film was dried at 70 ° C. for 2 minutes to obtain a polarizer. The polarizer had a thickness of 30 μm and a moisture content of 14.3% by weight.

[Adhesive applied to transparent protective film]
Polyvinyl alcohol resin having an acetoacetyl group (average polymerization degree 1200, saponification degree 98.5% mol%, acetoacetyl group modification degree 5 mol%) 100 parts by weight, 50 parts by weight of methylol melamine at 30 ° C. It melt | dissolved in the pure water under temperature conditions, and prepared the aqueous solution with a solid content density | concentration of 3.7 weight%. A metal colloid-containing adhesive aqueous solution was prepared by adding 18 parts by weight of an aqueous solution containing a positively charged alumina colloid (average particle diameter of 15 nm) at a solid concentration of 10% by weight to 100 parts by weight of this aqueous solution. The viscosity of the adhesive solution was 9.6 mPa · s, the pH was in the range of 4 to 4.5, and the compounding amount of the alumina colloid was 74 parts by weight with respect to 100 parts by weight of the polyvinyl alcohol resin. The average particle size of the alumina colloid is measured by a dynamic light scattering method (light correlation method) with a particle size distribution meter (manufactured by Nikkiso, product name “Nanotrack UAP150”).

[Formation of adhesive layer]
<Preparation of acrylic polymer>
In a reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer and a stirrer, 100 parts of butyl acrylate, 3 parts of acrylic acid, 0.1 part of 2-hydroxyethyl acrylate and 2,2′-azobisisobutyrate A solution was prepared by adding 0.3 parts of ronitrile with ethyl acetate. Next, the solution was stirred while blowing nitrogen gas and reacted at 55 ° C. for 8 hours to obtain a solution containing an acrylic polymer having a weight average molecular weight of 2.2 million. Furthermore, the acrylic polymer solution which added ethyl acetate to the solution containing this acrylic polymer and adjusted solid content concentration to 30% was obtained.

As a cross-linking agent, 100 parts by weight of the solid content of the acrylic polymer solution is a cross-linking agent mainly composed of a compound having an isocyanate group of 0.5 part (trade name “Coronate L” manufactured by Nippon Polyurethane Co., Ltd.). And 0.075 parts of γ-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “KMB-403”) as a silane coupling agent in this order, Was prepared. The pressure-sensitive adhesive solution was applied to the surface of a release sheet composed of a peeled polyethylene terephthalate film (thickness 38 μm) so that the thickness after drying was 25 μm and dried to form a pressure-sensitive adhesive layer.

[Transparent protective film]
A 80 μm thick triacetylcellulose film (trade name “TD-TAC” manufactured by Fuji Film Co., Ltd.) was used.

Example 1
[Creation of polarizing plate]
A roll machine is used on one side of the polarizer, with the adhesive applied to one side of the transparent protective film so that the thickness of the adhesive layer after drying is 80 nm. Were bonded together and dried at 70 ° C. for 6 minutes to prepare a polarizing plate having a transparent protective film only on one side.

[Protective layer forming agent]
A cyanoacrylate-based forming agent (trade name: Aron Alpha, manufactured by Toa Gosei Co., Ltd.) was used.

[Creation of adhesive-type polarizing plate]
The cyanoacrylate-based forming agent is applied to the polarizer surface (polarizer surface on which the transparent protective film is not provided) of the polarizing plate so as to have a thickness of 3 μm with a bar coater. Post cure was performed for 2 seconds. Thereafter, the pressure-sensitive adhesive layer formed on the release-treated surface of the release sheet was bonded to prepare a pressure-sensitive adhesive polarizing plate.

Example 2
[Protective layer forming agent]
An epoxy-based forming agent (trade names: Cemedine, manufactured by Cemedine Co., Ltd.) was used.

[Creation of adhesive-type polarizing plate]
The thickness of the epoxy-based forming agent after drying with a bar coater is 3 μm on the polarizer surface (polarizer surface not provided with a transparent protective film) of the polarizing plate obtained in Example 1. And post-cured at 50 ° C. for 3 minutes. Thereafter, the pressure-sensitive adhesive layer formed on the release-treated surface of the release sheet was bonded to prepare a pressure-sensitive adhesive polarizing plate.

Example 3
[Protective layer forming agent]
1,8-diazabicyclo [5,4,0] -undecene-7 (trade name “DBU”, San Apro Co., Ltd.) is added to 100 parts by weight of an isocyanate forming agent (trade name Aquanate, manufactured by Nippon Polyurethane Industry Co., Ltd.). (Manufactured) 0.2 parts by weight were added, and a solution obtained by diluting them with water at 100 parts by weight was used.

[Creation of adhesive-type polarizing plate]
The thickness of the above-mentioned isocyanate-based agent solution after drying with a bar coater on the polarizer surface (polarizer surface not provided with a transparent protective film) of the polarizing plate obtained in Example 1 is 1. It apply | coated so that it might become 5 micrometers, and postcure was performed for 5 minutes at 50 degreeC. Thereafter, the pressure-sensitive adhesive layer formed on the release-treated surface of the release sheet was bonded to prepare a pressure-sensitive adhesive polarizing plate.

Example 4
[Protective layer forming agent]
100 parts by weight of an acrylic resin raw material (manufactured by DIC Corporation, trade name: GRANDICPC1071) containing a curable component at a solid concentration of 66% by weight in a mixed solvent (butyl acetate: ethyl acetate (weight ratio) = 89: 11) A resin component was prepared by blending 3 parts by weight of a photopolymerization initiator (manufactured by Ciba Specialty Chemicals, trade name; Irgacure 907) with (solid content). This resin component was diluted with ethyl acetate so that the solid content concentration was 55% by weight, and a solution of an active energy ray-curable forming agent was used.

[Creation of adhesive-type polarizing plate]
After drying the solution of the active energy ray-curable forming agent prepared above on the polarizer surface (polarizer surface not provided with a transparent protective film) of the polarizing plate obtained in Example 1 with a bar coater The film was applied to a thickness of 10 μm and heated at 80 ° C. for 2 minutes to form a coating film. Thereafter, the protective layer was formed by irradiating with an ultraviolet ray having an integrated light quantity of 300 mJ / cm ^{2 by} a metahalide lamp and performing a curing treatment. Thereafter, the pressure-sensitive adhesive layer formed on the release-treated surface of the release sheet was bonded to prepare a pressure-sensitive adhesive polarizing plate.

Example 5
[Protective layer forming agent]
A solution in which 2 parts by weight of a photopolymerization initiator (manufactured by Ciba Specialty Chemicals, trade name: Irgacure 907) was blended with 100 parts by weight of hydroxyethyl acrylic was used as an active energy ray curable forming agent.

[Creation of adhesive-type polarizing plate]
After drying the solution of the active energy ray-curable forming agent prepared above on the polarizer surface (polarizer surface not provided with a transparent protective film) of the polarizing plate obtained in Example 1 with a bar coater After coating to a thickness of 10 μm, a protective layer is formed by irradiating with a high-pressure mercury lamp for 30 seconds (integrated light amount 1200 mJ / cm ² ) with an illuminance of 40 mW / cm ² for 30 seconds. Formed. Thereafter, the pressure-sensitive adhesive layer formed on the release-treated surface of the release sheet was bonded to prepare a pressure-sensitive adhesive polarizing plate.

Example 6
[Creation of adhesive-type polarizing plate]
In Example 4, an adhesive polarizing plate was prepared by the same method as in Example 4 except that the solution of the active energy ray-curable forming agent was applied so that the thickness of the protective layer was 5 μm.

In addition, when the adhesive type polarizing plate obtained in Example 6 was observed on the backlight, the transmitted light unevenness of crossed Nicol formation was less than that of the adhesive type polarizing plate obtained in Example 4. It was. This is because the pressure-sensitive adhesive polarizing plate obtained in Example 6 was thinner than the pressure-sensitive adhesive polarizing plate obtained in Example 4, and thus transmitted light unevenness due to the influence of the retardation of the protective layer was reduced. .

Comparative Example 1
[Creation of adhesive-type polarizing plate]
The pressure-sensitive adhesive layer formed on the release-treated surface of the release sheet was bonded to the polarizer surface (polarizer surface not provided with a transparent protective film) of the polarizing plate obtained in Example 1, and the pressure-sensitive adhesive type. A polarizing plate was created.

Comparative Example 2
[Protective layer forming agent]
A polyvinyl acetate adhesive (trade name: Gohsenil, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) was used.

[Creation of adhesive-type polarizing plate]
The polyvinyl acetate adhesive is applied to the polarizer surface of the polarizing plate obtained in Example 1 (the polarizer surface not provided with the transparent protective film), and the thickness after drying with a bar coater is 3 μm. Then, post-curing was performed at 50 ° C. for 3 minutes. Thereafter, the pressure-sensitive adhesive layer formed on the release-treated surface of the release sheet was bonded to prepare a pressure-sensitive adhesive polarizing plate.

Comparative Example 3
[Creation of adhesive-type polarizing plate]
The protective layer forming agent (solution) prepared in Example 4 was applied to both sides of the polarizer so that the thickness after drying was 10 μm with a bar coater, and heated at 80 ° C. for 2 minutes. Formed. Thereafter, a meta-halide lamp was irradiated with ultraviolet light with an integrated light quantity of 300 mJ / cm ² to perform a curing treatment, thereby producing a polarizing plate having protective layers on both sides of the polarizer. Then, the adhesive layer formed in the peeling process surface of the said release sheet was bonded together to the protective layer of the single side | surface of the obtained polarizing plate, and the adhesive type polarizing plate was created.

Comparative Example 4
[Protective layer forming agent]
Emulsion polyurethane resin (Daiichi Kogyo Seiyaku Co., Ltd., trade name: Superflex 460) was used.

[Creation of adhesive-type polarizing plate]
The aqueous polyurethane resin was applied to a norbornene-based film (Zeon Corporation, ZEONOR film) having a thickness of 100 μm so that the thickness after drying with a bar coater was 10 μm, and 3 minutes in a dryer at 80 ° C. Dried to form a protective layer. The protective layer was bonded to the polarizer surface of the polarizing plate obtained in Example 1 (polarizer surface not provided with a transparent protective film) with a laminator, and further dried at 80 ° C. for 2 minutes. The material (Zeonor film) was peeled off. Thereafter, the pressure-sensitive adhesive layer formed on the release-treated surface of the release sheet was bonded to prepare a pressure-sensitive adhesive polarizing plate.

Comparative Example 5
[Creation of adhesive-type polarizing plate]
By applying the active energy ray-curable forming agent solution prepared in Example 5 on both sides of the polarizer so that the thickness after drying is 10 μm with a bar coater, and heating at 80 ° C. for 2 minutes. A coating film was formed. Thereafter, a meta-halide lamp was irradiated with ultraviolet light with an integrated light quantity of 300 mJ / cm ² to perform a curing treatment, thereby producing a polarizing plate having protective layers on both sides of the polarizer. Then, the adhesive layer formed in the peeling process surface of the said release sheet was bonded together to the protective layer of the single side | surface of the obtained polarizing plate, and the adhesive type polarizing plate was created.

The following evaluation was performed on the pressure-sensitive adhesive polarizing plates obtained in the above Examples and Comparative Examples. The results are shown in Table 1. In measuring the tensile elastic modulus, a sample is sandwiched between SUS plates, a protective layer forming agent is injected into the frame, and cured under the same conditions as in each example, and the sample is 120 mm long, 120 mm wide, and 100 μm thick. Was prepared. When the protective layer forming agent is an active energy ray curable forming agent, a frame is placed on a SUS plate, the forming agent is poured into the SUS plate, and active energy rays are irradiated from the forming agent side under the same conditions as in each example. Cured.

<Tensile modulus>
A sample piece having a width of 10 mm and a length of 100 mm is cut into a strip shape, and the strip-like sample is pulled in the longitudinal direction under a temperature environment of 25 ° C. using a universal tensile compression tester (Tensilon) under the following conditions. The tensile elastic modulus was determined from the obtained SS (Strain-Strength) curve. As measurement conditions, the tensile speed is 50 mm / min, the distance between chucks is 50 mm, and the measurement temperature is room temperature. The method of obtaining the elastic modulus from the SS curve is to draw a tangent at the initial rise of the SS curve, read the strength at the position where the tangent extension reaches 100% elongation, and measure the value. The value obtained by dividing by the cross-sectional area (thickness × sample width (10 mm)) was taken as the tensile modulus (generally referred to as Young's modulus).

<Durability>
The obtained polarizing plate was cut into a 15-inch diagonal size, and a sample was prepared by laminating both sides of a 0.5 mm-thick alkali-free glass in the crossed Nicols direction. The sample was subjected to a heat shock of −40 to 85 ° C. for 30 minutes × 100 times in each environment, and then taken out and visually confirmed whether cracks (number) were generated on the polarizing plate. This test was performed five times.

In the case of the sample size (15-inch size) subjected to the above evaluation, if the average number of cracks generated is 2 or less, for example, in a polarizing plate having a small size for mobile use, cracks do not occur in actual use. Therefore, it can be said that the polarizing plate for mobile use can satisfy the durability if the tensile elastic modulus of the protective layer is 100 MPa or more. In addition, for example, in order for the screen size to be the same as the main evaluation (15 inch size) and no cracks are generated, the average crack is required to be less than one. Therefore, it can be said that the 15-inch polarizing plate can satisfy the durability if the tensile elastic modulus of the protective layer is 500 MPa or more. Further, for example, when the screen size becomes large, such as a TV, it is required that no cracks are generated in an evaluation experiment of a sample size (15 inches). Therefore, it can be said that the durability of the large polarizing plate such as TV can be satisfied if the tensile elastic modulus of the protective layer is 1000 MPa or more.

P Polarizer E Transparent protective film G Adhesive layer H Protective layer B Adhesive layer

Claims

A transparent protective film (E) is provided only on one side of the polarizer (P) via an adhesive layer (G), and the other side of the polarizer (P) is protected with a tensile modulus of 100 MPa or more. An adhesive polarizing plate, wherein the adhesive layer (B) is provided via the layer (H).
The protective layer forming agent (H ') for forming the protective layer (H) is a cyanoacrylate-based forming agent, an epoxy-based forming agent, an isocyanate-based forming agent, or an acrylic-based forming agent. The adhesive polarizing plate as described.
The pressure-sensitive adhesive polarizing plate according to claim 1, wherein the protective layer forming agent (H ') for forming the protective layer (H) is an active energy ray curable forming agent containing a curable component.
The pressure-sensitive adhesive polarization according to claim 1, wherein the protective layer (H) satisfies a photoelastic coefficient (m 2 / N) × thickness (m) ≦ 1 × 10 −14 (m 2 / N). Board.
A transparent protective film (E) is provided only on one side of the polarizer (P) via an adhesive layer (G), and the other side of the polarizer (P) is provided via a protective layer (H). A pressure-sensitive adhesive layer (B) provided with a pressure-sensitive adhesive polarizing plate,
The protective layer (H) has a tensile modulus of 100 MPa or more,
In the lamination of the polarizer (P) and the pressure-sensitive adhesive layer (B), a protective layer (H) is formed on one surface of the polarizer (P), and then the pressure-sensitive adhesive layer (B) is formed on the protective layer (H). A method for producing a pressure-sensitive adhesive polarizing plate, comprising: laminating layers.
The protective layer forming agent (H ′) for forming the protective layer (H) is a cyanoacrylate-based forming agent, an epoxy-based forming agent, an isocyanate-based forming agent, or an acrylic-based forming agent. The manufacturing method of the adhesive type polarizing plate of description.
6. The production of the pressure-sensitive adhesive polarizing plate according to claim 5, wherein the protective layer forming agent (H ′) for forming the protective layer (H) is an active energy ray curable forming agent containing a curable component. Method.
The pressure-sensitive adhesive polarization according to claim 5, wherein the protective layer (H) satisfies a photoelastic coefficient (m 2 / N) × thickness (m) ≦ 1 × 10 −14 (m 2 / N). A manufacturing method of a board.
An image display device comprising the pressure-sensitive adhesive polarizing plate according to any one of claims 1 to 4.
A method for manufacturing an image display device, comprising:
A roll original fabric preparation step of preparing the long sheet of the pressure-sensitive adhesive polarizing plate according to any one of claims 1 to 4 as a roll original fabric,
A sheet cutting process for unwinding the sheet product from the roll and cutting the adhesive polarizing plate into a predetermined size using a cutting means;
After the cutting step, a bonding step of bonding to the optical display unit via the pressure-sensitive adhesive layer (B) of the pressure-sensitive adhesive polarizing plate;
A method for manufacturing an image display device having